1 files changed, 87 insertions, 0 deletions
diff --git a/tests/bench/transactional/ReaderMonadic.scala b/tests/bench/transactional/ReaderMonadic.scala
new file mode 100644
index 000000000..ce69c35ad
--- /dev/null
+++ b/tests/bench/transactional/ReaderMonadic.scala
@@ -0,0 +1,87 @@
+package transactional
+
+case class Reader[R,A](run: R => A) {
+  def map[B](f: A => B): Reader[R, B] = Reader(r => f(run(r)))
+  def flatMap[B](f: A => Reader[R, B]): Reader[R, B] = Reader(r => f(run(r)).run(r))
+}
+
+object Reader {
+  def ask[R]: Reader[R,R] = Reader(r => r)
+}
+
+object ReaderBench extends Benchmark {
+  type Transactional[T] = Reader[Transaction, T]
+
+  def transaction[T](op: Transactional[T]): T = {
+    implicit val trans: Transaction = new Transaction
+    val res = op.run(trans)
+    trans.commit()
+    res
+  }
+
+  def thisTransaction: Transactional[Transaction] = Reader.ask
+
+  abstract class Op {
+    def f(x: Int): Transactional[Int]
+  }
+
+  class Op0 extends Op {
+    def f(x: Int): Transactional[Int] =
+      for (trans <- thisTransaction)
+      yield { trans.println("0th step"); x }
+  }
+
+  class Op1 extends Op {
+    def f(x: Int): Transactional[Int] =
+      for (trans <- thisTransaction)
+      yield { trans.println("first step"); x + 1 }
+  }
+
+  class Op2 extends Op {
+    def f(x: Int): Transactional[Int] =
+      for (trans <- thisTransaction)
+      yield { trans.println("second step"); x + 2 }
+  }
+
+  class Op3 extends Op {
+    def f(x: Int): Transactional[Int] =
+      for (trans <- thisTransaction)
+      yield { trans.println("third step"); x + 3 }
+  }
+
+  val op = Array[Op](new Op0, new Op1, new Op2, new Op3)
+
+  def f(x: Int, n: Int): Transactional[Int] = {
+    def rest(trans: Transaction): Transactional[Int] = {
+      trans.println("fourth step")
+      if (n > 0) {
+        for {
+          y <- op(n % 4).f(x)
+          z <- f(y: Int, n - 1)
+        }
+        yield z
+      }
+      else {
+        if (x % 2 != 0)
+          for (trans <- thisTransaction)
+          yield { trans.abort(); () }
+        Reader(_ => x)
+      }
+    }
+    thisTransaction.flatMap(rest)
+  }
+
+  def run(): Int = {
+    transaction {
+      for (res <- f(7, 10))
+      yield {
+        for (trans <- thisTransaction)
+        yield { assert(!trans.isAborted); () }
+        assert(res == 22)
+        res
+      }
+    }
+  }
+}
+
+object ReaderMonadic extends Runner("reader monadic", ReaderBench, 22)